Delete Keyframes in Rig
You can delete a concrete animation data keyframes in a Dope Sheet Editor.
In this example I have two bones which have separate rotation animation.



Arm rotates 60 degrees and forearm rotates 30 degrees.



If you want to delete a forearm rotation for example you go to the Dope Sheet Editor, select the dots (which represent the keyframes) that belong to forearm bone and delete them (hover the curor over timeline in Dope Sheet editor window and press X).



Now when you play the animation only the rotation of an arm bone remains.